1. Grandpa is most likely an old perv.
2. Tell her to go after the millions, nothing prevent her from continue being friends with the halfway kids afterwards. If she stops being friends with them, means they friendship worth nothing to Ashley to begin with. That would be the true test of Ashley's friendship.
I am probably conditioned by the various games on the forum, I always expect certain characters to behave in a certain way. But the attitude of Madelein and the grandfather does not convince me, there is something between the two, perhaps nothing perverse, but it does not seem to me a normal master-waitress relationship.1) I think he's meant to give off the vibes of being an old lech, as men in his position often tend to be, but I don't think he is one. As for Madeleine, I don't there's anything sexual there, just the same lecherous behaviour but nothing more than that.
2) I would recommend that she remember why she rebelled in the first place; because she didn't want that kind of life for herself. Nothing has changed, as far as I can tell, as Ashley doesn't seem to want or enjoy that elitist lifestyle. She might feel bad about abandonding her sister because of her selfish actions, but she shouldn't let that guilt her into returning to a life she was never comfortable with.
I also found what the Grandfather said about himself interesting, about how he built his company and lifestyle by himself with his "own 2 hands", because that's what Ashley's trying to do now. She wants to build a life for herself, not take on someone else's legacy, and I'd like to think that her Grandfather could accept that as he might very well respect the self-made man, or in this case woman, because he is a self-made man.
I don't think it will be easy to remain friends with Emily and the MC if she comes home to Lexington. Grandpa seems to me the classic authoritarian type and ready to do anything for her purposes, this is something that Lynn is right about, if Ash goes back to the Lexingtons his grandfather will make sure that she interrupts her relations with them.
It doesn't seem to me that Ashley ran away because she didn't like being rich, I think her problem was with her parents, or at least I understand that.
Grandpa definitely has esteem for her, the girl has proven to be different from the parasites that usually surround him, but he remains an authoritarian man, now that he has proof that Ashley has the right character, similar to his, he wants her to come back and follow the path that he has decided anyway.
I believe that for her sake, Ashley should stay away from the Lexingtons as much as possible.